Re: futex: priority wakeup miss ordering

From: Andrew Morton
Date: Thu May 08 2008 - 04:26:15 EST


On Wed, 07 May 2008 14:22:58 -0700 Daniel Walker <dwalker@xxxxxxxxxx> wrote:

>
>
> from commit ec92d08292d3e9b0823eba138a4564d2d39f25c7
>
> The wakeup ordering should be in priority order. However if the priority
> of a task is modified while it's waiting on the futex you will get an
> out of order wakeup.
>
> If you use a priority inheriting mutex this is correct. It's because the
> rtmutex hooks into sched_setscheduler to catch any priority changes,
> then re-queues with the new priority.. But the futex doesn't have this
> hook.
>
> Was this intentionally left out of this priority wake up patch? I
> thought I would let you know in case you had a specific reason for not
> handling this..
>

Pierre is no longer @bull.net.
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